Robotics have been incorporated into analytical instruments in various ways. The most common use of robotics in these instruments has been to transport a pipette to aspirate liquid from a test tube. Another use of robotics has been to transport a test tube rack within an automated testing system, as described in U.S. Pat. No. 5,260,872.
Robotics have also been used to transport test tubes within an instrument. For example, U.S. Pat. No. 4,835,711 to Hutchins et al. illustrates a robotic arm transporting a test tube to various work stations which are placed in a circle around the robotic arm. The robotic arm is mounted to a fixed position on the workstation and rotates about an axis perpendicular to the surface of the workstation. As illustrated, the test tube appears to be gripped within gripper fingers, the ends of which are curved in the shape of the test tube. No provision is made to transport containers other than test tubes.
Another robotic arm for transporting a test tube is shown in International Publication No. WO 90/03834. This robotic arm rotates and may lift or lower the test tube but the robotic arm is not translatable along any axis. The gripper fingers are only shown and described as gripping a test tube.
U.S. Pat. No. 4,835,707 to Amano et al. describes a robotic arm that is mounted to the central portion of the workstation and articulates in the x, y, and z axes and rotates in the theta direction. The robot may grasp a sample tube or one of various circular nozzles on the workstation with a chuck.
International Publication No. WO 93/15407 describes the movement of a test tube with a robotic arm with a "hand" to carry the test tube between a mosaic of tesserae of devices and subsidiary devices. The robotic arm may move along a rail in a first axis and a horizontal arm is translatable along second and third axes (vertically and horizontally) and is pivotable about an axis of rotation. This application also teaches that more than one similar apparatuses may be adjoined by and cooperate with another by extending the rails supporting the robots to extend over the adjoining apparatus.
While extending a rail from one apparatus to another similar apparatus is one approach to moving a robotic arm between instruments, this approach is not ideal for transporting objects between more than a few instruments as the rail along which the robotic arm must move becomes significantly long. A better alternative is to use a lab automation transport line to transport test tubes between instruments positioned along the side of the transport line. One such transport line is described in U.S. Pat. No. 5,623,415 to O'Bryan and assigned to SmithKline Beecham Corporation. In the O'Bryan patent, a generic pick-and-place engine, with a robotic arm and grip, is referenced as the means for transferring test tubes between the transport line and the instruments. Alternatively, a pipetting engine may pipette specimens of samples from the test tubes in the transport line for use by the instrument.